diff --git a/doc/Doxyfile.in b/doc/Doxyfile.in
index 4d9dc63bf..f8cdbf528 100644
--- a/doc/Doxyfile.in
+++ b/doc/Doxyfile.in
@@ -38,6 +38,7 @@ IGNORE_PREFIX          = pw_ \
                          spa_ \
                          SPA_
 GENERATE_TREEVIEW      = YES
+DISABLE_INDEX          = NO
 SEARCHENGINE           = YES
 GENERATE_LATEX         = NO